Just sharing this in case it helps others, since I had to deal with some issues for several hours over the past week, that I ultimately found out, were based on downloading GP4 mods carelessly, trusting that freeware that is used by many for a very old game, would be safe, since they are established in the community.
I've been setting up GP4 and going through all the motions to get it correctly working for a YouTube project I am planning. Its all on the same machine for me that I work from. Over the past weeks I downloaded several things here that would be considered "standard" when you set up GP4 for modern machines. A retro F1 mod, ZaZ Tools, GPxPatch, ... My machine is always clean, I pay for security software and have daily deep scans when I am not on the PC as well as all safety measures that you could have (which prevented worse from happening).
But during my setting up I started getting messages about outbound connections being blocked to strange, malicious websites. This means that something on your PC is trying to open malicious websites without your consent. Due to the softwares I am running those were blocked, but the origin wasn't detected. With the help of support from the security software I am using, the source was found, these two files were infected - and it wasn't false alarms either, because they made several attempts to open malicious websites:
gp4_exe_patch.exe (Malware.Heuristic.2047)
gp4tweaker_v1045_reloaded.rar (Malware.AI.2564140197)
Ultimately, after identifying the issue, I was able to remove the files and the malicious attempts have stopped immediately.
I don't know if the culprit was the source of the download (repackaged maliciously and redestributed) or if its the software itself, but I thought I share this here. I currently don't have GPxPatch and need to investigate how to get a clean version of it, to be able to run GP4 again without these threats. But yeah, thats all. Hope it helps to keep some of your safe.